Polyamide particles, production process therefor, resin composition, and molded article

Abstract

Polyamide particles including polyamide and having a water absorption rate of 0.5 to 2.5 wt. % are prepared to improve toughness of a cured product of a curable resin. The polyamide may be a semicrystalline polyamide. The polyamide has a glass transition temperature of approximately 100 to 150° C. The polyamide may have an alicyclic structure. The polyamide particles of this invention have an average particle size of approximately 5 to 40 μm and a specific surface area determined by the BET method of approximately 0.08 to 12 m2/g. The polyamide particles of the present invention may also be spherical and have an average particle size of approximately 15 to 25 μm. Furthermore, the polyamide particles of the present invention may have an exothermic peak in a temperature range between the glass transition temperature and a melting point of the polyamide upon heating the polyamide particles at a rate of 10° C./min by differential scanning calorimetry (DSC).

The invention claimed is: 
     
       1. Polyamide particles comprising:
 a polyamide having a water absorption rating of 0.5 to 2.5 wt. %; and 
 water in an amount of 0.5 to 2.5 wt %, wherein the polyamide particles have a specific surface area determined by the BET method of from 0.33 to 12 m 2 /g, wherein degree of crystallinity of the polyamide measured by differential scanning calorimetry (DSC) is 1 to 30%. 
 
     
     
       2. The polyamide particles according to  claim 1 , wherein the polyamide is a semicrystalline polyamide. 
     
     
       3. The polyamide particles according to  claim 1 , wherein a glass transition temperature of the polyamide is from 100 to 150° C. 
     
     
       4. The polyamide particles according to  claim 1 , wherein the polyamide is an alicyclic polyamide and/or an aliphatic polyamide. 
     
     
       5. The polyamide particles according to  claim 1 , which have an average particle size of from 5 to 40 μm. 
     
     
       6. The polyamide particles according to  claim 1 , wherein the polyamide particles have the specific surface area determined by the BET method of from 0.33 to 7·12 m 2 /g. 
     
     
       7. The polyamide particles according to  claim 1 , which are spherical and have an average particle size of 15 to 25 μm. 
     
     
       8. The polyamide particles according to  claim 1 , which have an exothermic peak in a temperature range between the glass transition temperature and a melting point of the polyamide upon heating the polyamide particles at a rate of 10° C./min by differential scanning calorimetry (DSC). 
     
     
       9. The polyamide particles according to  claim 1 , wherein degree of crystallinity of the polyamide measured by differential scanning calorimetry (DSC) is 80 or less. 
     
     
       10. The polyamide particles according to  claim 1 , wherein degree of crystallinity of the polyamide measured by differential scanning calorimetry (DSC) is 1 to 75%.